I don't know why you're hesitating!
In my opinion the 'different' cars are what keeps racing interesting. There's already a thousand Cavalier/Sunbird/Cobalt/whatever-else-had-the-same-bodystyle cars out there. Been there - done that - let's move on.
You're going to build a tube chassis race car with a small block chevy in it. It doesn't really matter what you dress it in. You might as well make sure that you won't be wearing the same dress as half the crowd when you get to the dance.
(if it's any consolation, I wanted to build an Opel Olympia wagon - I thought it would be cute, but the wife immediately vetoed it as too ugly...

)
Perry